books.google.com - With coverage on all the marine mammals of the world, authors Jefferson, Webber, and Pitman have created a user-friendly guide to identify marine mammals alive in nature (at sea or on the beach), dead specimens “in hand , and also to identify marine mammals based on features of the skull. This handy...http://books.google.com/books/about/Marine_Mammals_of_the_World_A_Comprehens.html?id=_IY2n07t7QYC&utm_source=gb-gplus-shareMarine Mammals of the World: A Comprehensive Guide to Their Identification